MIAMI – There are plenty of reasons to pull for the Dallas Mavericks in Game 6 of the 2011 NBA Finals, which tips off Sunday night, at 8 p.m. Eastern. They share the ball on offense, and despite the advancing age of their players, give maximum effort on defense. They have two veteran future Hall of Famers, Dirk Nowitzki and Jason Kidd, who deserve championship rings.

Or, like many basketball fans, you may never forgive LeBron James for “The Decision.”

And here’s another reason why it’s worth cheering the Mavs: Dallas has received key contributions from two guys who, if they joined your weekend warrior pick-up game, would totally look like they belonged.

Is Dallas, who hold a 3-2 advantage in the series, really going to win the NBA title with a 5’9” guy, J.J. Barea, starting at shooting guard? (Barea is listed as six feet tall, but don’t believe that for a second). Barea still gets mistaken for a trespasser: even this season, his 5th in the NBA, a security guard wouldn’t let him into an arena one night, since he didn’t believe that Barea actually played in the NBA. “I came out to say ‘hi’ to some friend, then I went back in, they didn’t want to let me go back in,” says Barea, recounting the tale before Dallas’ practice on Saturday. “The other guard had to come and [say], ‘yeah, he played tonight.’”

At least Barea isn’t confused for a grocery bagger, or a seventh-grade teacher, which Brian Cardinal, Dallas’ balding, 6’8” reserve forward, says happens to him. “He’s just a normal guy,” says Dallas reserve Corey Brewer. “He’s everybody’s favorite player, probably because it’s like anybody can play in the NBA when you see BC. It’s like, just the old white guy walking in the gym. Just an old white guy. He should be somewhere with his family, with three kids. Playing at the YMCA.”

Cardinal is fully aware that he doesn’t look the part. “Whatever NBA mold there is,” he says, “I’m not of that.”

Though it’s easy to relate to both Cardinal and Barea, their play has been anything but common. After all, they could be the key difference-makers for an NBA title team. Barea, especially, has been a force throughout the post-season. During Dallas’ second-round trouncing of the Los Angeles Lakers, Barea was such a pain in the rear for the Lakers that center Andrew Bynum finally flattened him, earning a $25,000 fine, and five-game suspension next season, for the vicious foul. He has started the last two games – both Dallas wins – in the Finals, and was huge in Thursday’s Game 5, nailing 4 of 5 three-pointers while scoring 17 points. “He’s a little faster when you see him in person,” says Miami Heat forward Udonis Haslem. “When you see him on TV, you wonder how this little guy does what he does. You’ve got to give him credit.”

Barea grew up in Puerto Rico, and was an undrafted free agent out of Northeastern University, no hoops powerhouse, before Dallas signed him in 2006. His speed isn’t blinding, but he has an uncanny knack for getting into the lane, and either hitting spinning layups over outstretched defense convinced they are going to block his shot into the stands, or finding an open shooter. He is used to being underestimated, though Barea realizes that opponents are starting to key in on him. “I noticed that defenses are paying more attention to me,” says Barea, who is dating a Zuleyka Rivera, the 2006 Miss Universe. “Definitely, in the pick and rolls, they are more reactive, I hear them talking about what they are going to do to me.”

If Miami wants to survive this series, the team can’t let Barea repeat his Game 5 outburst. “The guy hit four threes, three of them was at the end of the shot clock with him not even holding his follow-through,” says LeBron James. “A guy like that, once he gets into the lane and gets a few layups, his outside shot becomes better, just like a lot of us. Myself and D-Wade, if you allow us to get to two or three layups, we feel like we’re in a good rhythm. So we have to do a better job of trying to keep him out the paint. If you keep him out of the paint early, that’s better for us. He doesn’t shoot the ball as well as he would if he gets a few layups here, a few layups there, a couple of free-throws.”

Cardinal plays a different role. Miami is not fretting about him in the scouting reports. And he’s certainly not filling up the box score. During the four Finals games in which Cardinal has appeared, he’s played a mere 18 minutes. If veteran shooting specialist Peja Stojakovic wasn’t playing so woefully – on defense, Stojakovic has the “golden arm,” as every shot he tries to contest goes in – Cardinal would probably never leave the bench. If fact, when Dallas coach Rick Carlisle first barked “Cardinal” in Game 2, Cardinal says he thought Carlise was ordering him to clean up a spilled drink, not summoning him into the game.

Since he always sweeps the floor – with his body – Cardinal is nicknamed “The Custodian.” “He never thought he was good enough to play,” says Gene Keady, who was Cardinal’s coach at Purdue University. “Most kids aren’t as good as they think they are. With Brian, it was just the opposite.”

Cardinal has survived the cutthroat competition of the NBA because of his shooting touch, his willingness to sacrifice his body, and refusal to complain about playing time. Cardinal knows the NBA doesn’t employ many slow balding white dudes, so he’s appreciates the roster spot. His go-to move: a few prodding dribbles into the lane, and a bounce pass to a big-man. It’s not the stuff that makes SportsCenter. “I’ll work on ‘the move’ today,” Cardinal said before Saturday’s practice.

Don’t let all the self-deprecation fool you: Cardinal can have a positive impact for the Mavs. In Game 5, for example, he hit a first-half three-pointer that fired up the home crowd. He put himself in position to take charges against both James and Dwyane Wade; although he crashed to the floor both times, he got neither call, and the refs whistled Cardinal for a blocking foul instead. “Oh, I don’t know,” Cardinal responds when asked why he didn’t get the call, saying “Oh” like a character from Fargo (Cardinal is from Tolono, Illinois, in the central part of the state). “There are a variety of reasons that I am sure that are out there.” Like, on a bang-bang play, the bald bench guy is not going to get a call against superstars. “Oh, I don’t think so, um, you know…” Cardinal pauses. You don’t want to get fined, right? “No,” he says.

Although he didn’t get the call, Wade bruised his hip on that play involving Cardinal. Wade missed the start of the second half to get treatment: if it continues to bother him, Cardinal’s bodily sacrifice could be a huge difference in this series (on Saturday, Wade insisted that his hip would be fine). Maybe Cardinal’s strength was too much for Wade to handle? “Well,” Cardinal takes a deep breath. “No. I’d love to say yes. I mean, maybe I’m too bony.”

Coming into Game 6, all eyes will be on LeBron, as the world waits to see how he responds to another subpar scoring effort. But watch Barea and Cardinal too. They may look like they belong at the Y. But you won’t be seeing them there this summer. They may be lifting the championship trophy instead.